Glugging lots of sugary drinks won't just make you fat, it might also lead to changes in the brain that have been linked to cancer and Alzheimer's disease -- at least in rats.
This finding comes from the first analysis of how sugary drinks affect proteins in the brain. It showed that 20 per cent of the proteins produced in a brain region related to decision-making were different in rats that drank sugary drinks from those of rats that had been given water.
It is well established that drinking sugar-sweetened drinks is linked to obesity and diabetes as well as to increased risk of cardiovascular problems. A recent estimate put the global number of deaths associated with soft drinks at 184,000 a year.
But the effects of sugar-rich drinks on the brain have received much less attention. "For many people around the world, soft drinks are their sole source of liquid, or at least they provide a very high proportion of their daily calories," says Jane Franklin of the behavioural neuropharmacology lab at Macquarie University in Sydney, who carried out the new analysis. "We know that soft drinks are bad for the body, so it's reasonable to assume that they aren't doing anything good for your brain, either."
To confirm that assumption, Franklin and her colleague Jennifer Cornish gave 24 adult rats either water or a solution of water containing 10 percent sugar -- about the proportion you would find in a typical can of soda -- for 26 days.
For the following seven days, both groups were given only water. At the end of that time, the rats that drank the sugary drink were significantly more hyperactive -- spending lots more time moving around -- than the control group. "Hyperactivity is a physical sign that something unusual is happening in the brain," Franklin says. It is probably a reflection of changes being made to return the system back to its pre-sugar state, after it had adjusted to prolonged sugar consumption, she says.
To find out what was going on, the team looked at the rats' orbital frontal cortex.
Of the 1,373 proteins identified there in both sets of rats, 290 were altered in those that drank sugary drinks but not those that drank water.
-- New Scientist